DESCRIPTION: (Applicant's Abstract) There is considerable evidence that treatment for cocaine addiction can lead to significant improvements in substance use and psychosocial problem severity. However, a significant percentage of patients relapse to cocaine abuse or dependence after primary treatment has ended. In some programs, patients are therefore referred to aftercare in an effort to prevent relapse and decrease the probability of additional rehabilitation treatments. Given the enormous social costs of cocaine addiction and the comparatively small resources for treatment, the appropriate use of aftercare could potentially have a large economic impact. However, there have only been a few studies of aftercare for cocaine patients. In particular, there is very little empirical information on the effectiveness of aftercare compared to minimal or no aftercare. Furthermore, there is virtually no information on the cost-effectiveness of aftercare for cocaine patients. In this health services study, which builds on findings generated from a previous NIDA-funded cocaine aftercare study, we propose to evaluate the effectiveness and cost-effectiveness of three approaches to aftercare. Cocaine dependent patients who complete day hospital rehabilitation will be randomly assigned to one of the following interventions: (1) Minimal aftercare (MIN), a combination of referral to self-help groups and brief telephone case-management; (2) Standard disease-model aftercare counseling (STND), provided through two group therapy sessions per week; and (3) Individualized aftercare (IND), provided through one individual cognitive-behavioral, relapse prevention session and one group therapy session per week. Each aftercare intervention will be 12 weeks in duration. Patients will be followed up at 3, 6, 9, 12, 18, and 24 months post intake into aftercare. Follow-up assessments will include measures of drug and alcohol use (self-report, collateral reports, and urine toxicology), HIV high-risk behaviors, psychosocial problem severity, and utilization of health and social services. In the analyses to determine treatment effectiveness, outcomes are predicted to be best in IND, followed by STND and MIN, with the difference between IND and STND increasing over the course of the follow-up. With regard to patient-treatment matching, patients who do not achieve consistent abstinence in IOP are predicted to have differentially better outcomes in IND than in STND or MIN, and those with high psychiatric severity will have differentially better outcomes in IND and STND than in MIN. Two secondary matching hypotheses will also be examined. For the cost-effectiveness component of the project, we will assess aftercare costs, other health costs (e.g., additional inpatient and outpatient treatment), and other economic costs (e.g., medical, crime, accidents, productivity). These data will be used to perform a comprehensive analysis of the cost-effectiveness of aftercare for cocaine patients. Furthermore, the cost-effectiveness of different approaches to aftercare for specific subgroups of patients will be determined. Overall, the STND condition is expected to be the most cost-effective form of aftercare. However, it is expected that MIN aftercare will be cost-effective for low problem severity ("good prognosis") patients, whereas IND aftercare will be cost-effective for high problem severity ("poor prognosis") patients.